yet another that doesn't make sense to me:
¿Cómo son las ciudades de México?
=
What are the cities in Mexico like?
literally: "as are the cities in Mexico?"

i suspect it's idiomatic, end of discussion ?

Question

yet another that doesn't make sense to me:
¿Cómo son las ciudades de México?
= 
What are the cities in Mexico like?
literally: "as are the cities in Mexico?"

i suspect it's idiomatic, end of discussion ?

Answer

Hey, your translation of "cómo" as "as" is not correct in this context.

Cómo with an accent is always translated as "how", is interrogativa.
Como is "as" when it is synonym with "like" in comparison.

For example, what I wrote earlier:

-Tu traducción de 'cómo' como 'as' no  es correcta en este contexto.
-Tu casa se ve como la casa de la vecina.

There is also 'tanto como/tan___como' that means 'as much as':

-Aprender español es tan difícil como aprender francés.
-Elena trabaja tanto como Inés.

Hope this helps you! If you have any doubt don't hesitate on contacting me :)

Answer

You can't always translate everything directly, but in this case you can. "Cómo" is functioning as an interrogative pronoun that can be translated as "how."

literally: How are the cities of Mexico?
or more loosely translated: What are the cities in Mexico like?

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